Humans have impacted the Earth to such a degree that many scientists believe it has shifted the natural evolution of the planet into a new phase. Future species or visiting little green men will discover the stratum of the crust in which humans drove themselves and the majority of other species into extinction, and talk about pre-human and post-human geological ages of the Earth.
The designation of a new geochronological epoch is proposed under the name of Anthropocene: it is to cover the period in which man has become one of the most important influencing factors on the biological, geological and atmospheric processes on earth.
"The Holocene epoch began at the end of the last Ice Age: 11,700 years ago. The world population grew quickly after that, and in recent decades it has begun to alter the Earth’s system so drastically in such a brief geological time, that we shall probably soon reach the limits of what the human species needs to exist. This is why it makes sense to announce a new epoch, the Anthropocene. As with many other geochronological units, this epoch is being initiated by a mass extinction, and it has already begun through human intervention. Nuclear experiments have released radionuclides that did not exist in the preceding 4.6 billion years in the history of the Earth. The use of fossil fuels that are millions of years old is releasing a huge quantity of greenhouse gases.
This in itself is not unique in the history of the Earth, but the speed of change and the fact that a single species has triggered it knows no precedent. In certain areas, soil erosion caused by agriculture has brought about deposits of thick clay layers that are clearly different from ‘natural’ sediments. The ‘Maya clay’ in the Central American rainforest is impressive testimony to the impact of high civilisation.
In order for all scientists to be speaking the same language, the International Commission on Stratigraphy must also define this epoch precisely. Recent geological deposits offer different possible dates for the commencement of the Anthropocene, but this is not surprising given the different sediment-forming processes involved. What characteristic, human-induced layer the Commission ultimately chooses, and what date it determines for its starting point, is thus of secondary importance.
The stratigraphic marking of the start of the Anthropocene is not just symbolically significant. The epoch will signify a new state of things on the Earth’s system and also explain major trends in the chronology of numerous benchmarks. The striking shifts in geological deposits show clearly that we are not dealing with a short-lived phenomenon. The Anthropocene will not have to hide behind the Holocene in terms of its duration. Humans will have played a key role in the Anthropocene, and will serve future species as an index fossil in stratigraphic classification."
Flavio Anselmetti is a professor of quaternary geology and paleoclimatology at the University of Bern and was previously Head of Sedimentology at the Swiss water research institute, Eawag, in Dübendorf.